// 方式二
// 简化
// 时间：112ms - 24.29%
var isUgly = function(num) {
  if (num < 1) return false;
  while (num % 2 == 0) num /= 2;
  while (num % 3 == 0) num /= 3;
  while (num % 5 == 0) num /= 5;
  return num == 1;
};
console.log(isUgly(6));
